Acanthomorpha

Acanthomorpha is a diverse clade of ray-finned fishes, including percomorphs and other lineages characterized ancestrally by spiny fin rays.

Actinopterygii: Actinopterygii is the vertebrate class comprising ray-finned fishes, whose fins are supported by bony rays. Acanthomorpha is nested within this much broader fish radiation.
Fin ray: A fin ray is a slender skeletal support element in the fin of a fish. The clade’s name alludes to the stiffened, often spinous fin rays found across its members.
Perciformes: Perciformes is a historically broad order of spiny-rayed fishes, including many familiar marine and freshwater forms. Its former breadth illustrates how classification within Acanthomorpha has been revised.
Cretaceous period: The Cretaceous is the geologic period from about 145 to 66 million years ago. Many early acanthomorph fossils and major lineage radiations date to this period.
Phylogenomic tree: A phylogenomic tree is an evolutionary tree inferred from many genes or genome-scale data. Genome-scale datasets test competing hypotheses for relationships within Acanthomorpha.
Teleostei: Teleostei is the largest infraclass of ray-finned fishes, containing most living fish species. Acanthomorphs form a major part of teleost diversity.
Dorsal fin: The dorsal fin is a fin located along the back of a fish. Changes in dorsal-fin structure distinguish many acanthomorph lineages.
Tetraodontiformes: Tetraodontiformes is an order of specialized fishes that includes puffers, triggerfishes, and ocean sunfishes. Its unusual body shapes exemplify the morphological range of acanthomorphs.
Cretaceous–Paleogene extinction event: The Cretaceous–Paleogene extinction event occurred about 66 million years ago and eliminated many species, including non-avian dinosaurs. Surviving fish lineages diversified in ecosystems transformed by this global extinction.
Incomplete lineage sorting: Incomplete lineage sorting occurs when ancestral genetic variants persist across successive species divergences. Rapid early splits can make gene trees disagree about the clade’s branching order.

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